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Very often it is not possible to get the planned apple harvest due to the attack of various pests. Timely detection and taking measures to protect the apple orchard comes to the fore.
Signs of defeat
The leafworm is a medium-sized butterfly, about 3 cm long, outwardly similar to a moth, has a gray color and a shaggy body. Leafworm babies are smooth caterpillars of a yellow-green hue, no more than 2 cm long, have 8 pairs of legs and a dark head.
The ability to mate appears just 3 days after leaving the pupa. Each butterfly lays up to 150 eggs per clutch.
In just 15 days, caterpillars will appear from these clutches, which will instantly crawl over the entire tree and begin to destroy it. Thus, due to a very short period of development, several generations of leaf rollers appear in one season. In September, preparation for winter begins, a leafworm weaves a cocoon from a web. And in the spring, when the first greens bloom, the caterpillars emerge from this cocoon and begin their life cycle anew.
Signs of damage vary, depending on the period:
- Early to mid-spring - spider webs on flowers and leaves, as well as eaten petals and leaf plates;
- Late spring-early summer - the leaves curl, and cocoons are visible on the veins and on the fruits;
- Mid and late summer - a thick white spider web with a silvery sheen on young branches, butterflies start to fly actively;
- Late summer-early fall - dark areas are visible on the leaves. These are ovipositions covered with a moist bloom from insect secretions;
- Mid-autumn - a large number of twisted leaves and cobweb-covered apples.
The need to fight the leaf roll
Caterpillars damage apple trees during the growing season. The first brood destroys the buds, therefore, the number of formed ovaries is significantly reduced. After the end of the flowering period, the insect moves to the top of the tree, eating leaves there. As a result, the foliage curls, and the tree begins to stun. As the fruits ripen, the caterpillars move onto them, gnawing holes. If we neglect timely measures to destroy this pest, then it will multiply to such an extent that it will begin to move from apple trees to other fruit trees and shrubs. With a global infection, you can lose an entire garden in one season.
Control measures
It is recommended to immediately begin active destruction of the pest in order to save not only the crop, but also the crown with its deciduous part. If a leaf roll is found on an apple tree, how to deal with this pest?
Chemical treatment
Before using chemicals, you need to assess the extent of the damage. Chemicals are an emergency measure when a pest has massively settled on an apple tree.If, during a random inspection of 25 inflorescences and leaf rosettes, 5 clutches of larvae were found, chemicals should be used.
The most effective insecticides:
- Inta-Vir is a drug with a wide range of action, as it destroys both young animals and adults. Processing is carried out at least 3.5 weeks before harvest. One tree requires 5 liters of ready-made solution;
- Avant - helps to get rid of larvae and caterpillars. It is allowed to process the apple tree 2 times with an interval of 15 days. The first spraying can be carried out when clutches are found, without waiting for hatching. The advantage of this tool is that the effect does not disappear after rain;
- Calypso - this tool can remove the leaf roll for a month. At the end of the period, you can spray the plants again. The drug is not harmful to beneficial insects (eg bees). In addition, the leafworm does not develop immunity against toxic components, which means that the effectiveness of Calypso does not decrease even with repeated use;
- Dimilin is a non-toxic drug for humans that has a toxic effect on the leafworm. The effect of the treatment lasts 6-7 weeks;
- Fastak is a concentrate in liquid form. Effectively destroys pests at any stage of their life cycle. The product is applied diluted through a spray bottle to leaves and branches. Does not lose its properties after precipitation and at high air temperatures.
All of these chemicals can only be applied before and after flowering or at the end of the season after harvest.
In case of massive damage during the formation of ovaries and fruits, it is allowed to use only biological means of protection, such as:
- Fitoverm is a concentrated preparation with economical consumption. Suitable for spraying during fruit formation. Retains its effectiveness in rainy weather and with a significant increase in temperature;
- Lepidocide is a powdery agent that is mixed with water and applied through a spray bottle. Can be used at any stage of apple tree development.
When choosing a product to spray apple trees, you need to pay attention to the growing season, the percentage of damage done and weather conditions. It is important not to miss the right time. In spring, apple trees need to be examined when the buds swell. If clutches are found on the buds and shoots, then the first spraying should be done when the buds turn pink.
When cocoons are found in the crevices of the bark, it is necessary to get rid of the pest when the buds swell and burst, releasing the tip of the leaf. Since this phase is very short-lived, you need to carefully monitor the tree so as not to miss the moment. With a timely response, the first generation of caterpillars can be destroyed in time, significantly reducing the number of leaf rollers. Also, the destruction of larvae during this period allows the apple tree to fully complete the flowering phase and form ovaries.
Folk ways
With a slight infection of apple trees with a leaf roll, you can get by with alternative methods of treatment:
- Spraying with herbal decoctions from Solanaceae or wormwood tops. For 1 part of the leaves, take 2 parts of water and boil for 30 minutes, leave for several hours and filter. The remaining broth is diluted with water to a volume of 10 liters, liquid soap is added to improve the adhesion of the product to the surface of the apple tree. Spraying should be done in the morning or evening in calm dry weather.
- Spraying with tobacco tincture. For 0.5 kg of tobacco, you need 10 liters of hot water. The mixture is infused for 3 days, after which it must be filtered and diluted with 20 liters of water with the addition of liquid soap.
- Making sweet traps. Sweet tea, jam, compote are poured into a plastic container. The container is placed overnight on a tree at least 1.5 m. In the morning, the trapped caterpillars must be destroyed.
- Making a sticky trap.Several fabric belts, abundantly greased with glue, can be attached to the tree trunk. You need to place the fabric at different heights, several pieces on each apple tree. Caterpillars will get stuck in the glue. In the fall, the belt is removed and burned.
Natural control measures
In a single case of finding a leaf roller on a tree, you can get by with collecting insects by hand. To do this, you need to quickly and accurately tear off the twisted sheet so that the caterpillar does not jump out of it. All collected leaves must be burned.
Preventive measures
Preventive measures to protect against leaf rollers are to follow the rules for caring for an apple orchard:
- Timely cleaning of the near-trunk circle from dry leaves and branches with their subsequent burning;
- Carrying out sanitary pruning, loosening and weeding of the soil;
- Carrying out formative pruning in order to exclude thickening of the crown. Normal branching of the apple tree not only protects against insects and diseases, but also has a beneficial effect on productivity;
- After autumn leaf fall, it is necessary to carry out hygienic cleaning of the bark. A stiff brush is used to brush off the dry layer of bark that forms crevices. This procedure also makes it possible to destroy the clutches already formed in the bark;
- The trunk must be whitewashed in autumn.
The leafworm is a dangerous and annoying insect that can return over and over again. Therefore, it is important to constantly monitor the apple trees, inspect and follow the cultivation techniques. Any disease is easier to prevent than to cure.